District of colxtjtbia



Aiig: 12 1924. 1,504,462

R. B. WOOLVERTON TfiK-NSIHSGION 0F RADIOSIGNALS EMPLOYING UNDAMPBD WAVES2 Sheets-Shaut 1 Filed July 25. 1921 Robe/1f 3. M10! Aug. 12 1924.1,504,462

R. B. WOOLVERTON TRANSMISSION OF RADIOSIGNALS EMPLOYING UNDAMPED WAVESFiled J y 25. 1921 2 Sheets-Shoot 2 @XGH Raberf B. Woo/verfbn PatentedAug. [2,

UNITED STATES PATENT or 1,504,462 FICE. a

ROBERT B. WOOLVERTOH, OF WASHINGTON, DISTRICT 01" COLUMBIA. TRANSMISSIONOF BADIOSIGNALS EMPLOYING UNDAMPED WAVES;

Application filed July 25, 1921. Serial No. 487,247.

To all wlwm it may concern:

. is not Be it known that I, Bonner B. Woonvna- TON, citizen of theUnited States, and residing at 'Washington, District of Columbia, haveinvented certain new and useful Improvements in the Transmission ofRadio-' s1 als Em loying, Undamped Waves, of w ich the ollowing is aspecification.

This invention relates to improvements in radio transmission apparatuswherein a generator of persistent or undamped oscillations, such as anarc generator, high freguency alternator or other source of energy iscmployed,-and has for an object, the provision of transmitting a paratusof such arrangement as will permit of rapid fluctations of the signalenergy with the come quent production of sharp rapid signals at areceivin station, a result, impossible to be obtained satisfactorily byuse of heretofore revalent apparatus.

Ot or objects will be in part obvious and in art pointed outhereinafter.

n the employment of generators such as I the arc and hi method heretoconnect the directly in the antenna circuit inorder to make the over-alleflicicncy as high as possible. The interruptions in the antenna circuitwere then produced by a varietyof methods such as by varying theinductance in the antenna circuit by short-circuiting the turns, or byconncctin across the generator an oscillatory circuit having a lowerresistance than the antenna circuit, so that by closing this oscillatoryor local tank circuit by means of a key, practically all of thegenerated radio frequency energy is diverted from the antenna tankcircuit. There are other means either employed, or discarded, but all sofar devised are unsatisfactory, because generally the factors, necessaryto be varied to produce variations in the antenna current, have been'tooeat, and tend therefore to-prevent rapi transmission.

Because of the constant advance in receiving apparatus, less energy neednow be h frequency alternator, the ore employed has been to generated inthe antenna circuit to cover a 'ven distance. Therefore, the over-allefciency of a generator of radio frequencies aramount, thisconsideration giving groun to that of rapid transmission, a conditionaccomplished through the instrumentalities of my invention.

source of, persistent oscillationscircuit to the It is thereforeproposed to provide means for destroying resonance between the antennaor radiating circuit and the closed or generating circuit in such amanner as to not only obviate any great variation in the elementsthemselves, but also to obviate the interruption of energy in theresonance destraying means. r

In order that the invention and its mode of application may be readilunderstood by persons skilled in the art, have, in the accompanyingillustrative drawin' and in the detai ed following description basedthereon, set forth several embodiments of the same.

In these drawings 'Figur'el is a diagrammatic view. of one form of thecircuit provided with intelli once formin means;

Figure 2 is a ragmentary iagrammatic view of the circuit wherein anelectro-static connection is employed in lieu of the inductivearrangement shown above, and

Figs. 3, 4 and 5 are fragmentary diagrammntic views showing modifiedforms of intelligence forming means.

Having more particular reference to the drawings, in connection withwhich like characters of reference will desi ate corresponding partsthereof, 1 indicates the drivin r circuit of a transmitting set ofundampe waves connecting a source of energy 2, a generator 3 which maybe either an arc generator as shown herein, a high frequency alternator,or any other generator of persistent oscillations such as conditions orpreference may dictate, and a choke coil 4, t e latter servin topreventthe returnof radio currents to t e source 2.

shunted about the generator 8 is a tuned oscillatory circuit comprisingconductors 5 connected inductively as at 6 to the antenna circuit 8,while a condenser 7 is interposed in one of the said conductors for anobvious purpose. Exact .resonance'is produced in the two. circuits socoupled, namely, the oscillatory and the antenna circuits, which,because of its extreme accurac dueto the employment of persistentoscillations, may be easily destroyed to completely prevent, or toprevent to a large degree, the transfer of energy from the generatorcircuit to the antenna circuit, at a desired fre uency. A very slightvariance of either t e capacitance or of the inductance in suchgenerator or antenna circuits will destroy exact resonance and byconsequence the current in the antenna circuit will either ceaseentirely, or will be sufiiciently reduced to produce the necessarysignal at the receiving station.

As means for effecting the production of signals, or more broadly,intelligence, a relatively small capacitance 9 is shunted about thecapacitance 7, and is so constructed as to ermit of appreciablevariation of its individual capacitance by a minimum of adjustment ofone or of both of its elements. The adjustment of the capacitance 9 isafl'ected through the medium of a solenoid 10, having the armaturethereof connected to but insulatedfrom, as at 11. one of the elements ofthe capacitance 9, which, as will be understood, is movable. The coil ofthe solenoid is connected in a circuit 12, having a key 13, interposedtherein, which, upon being 0 ened and closed will cause variation in t eture, there y causing rapid variations in the relative positioning ofthe capacitance element 9 'with the resultant rapid varia tion offrequency in the generator circuit whereby to produce correspondingrapid signals at a receiving station, due to the alternate establishmentand destruction of resonance between the generator and antenna circuits.

Instead of inductively coupling the oscillatory circuit to the antennasystem, it is to be also understood that the inductances 6' and 8' asshown in Figure 2, may be electrostatically connected by the condensers191 and 15, which, upon adjustment of the'elements of either thereof,will permit of rapid fluctuations in the antenna current by rea son ofthe destruction or partial destruction of the exact resonance normallyexisting between the generator and antenna circuits, thus producing aseries of corresponding rapid signals at the receiving station.

In Figure 3, I have shown a slightly modified form of employingintelligence forming means, employing herein the coils of a variometerindicated at 16 and connecting such coilsin series with one side of theoscillatory circuit formed by the. conductors 5. An intelligence formingkey 13' is interposed in the circuit 12' which in turn, includes thecircuit 10' whose armature is connected to butinsulated from an arm J7,having connection with one of the coils 16 of the variometer. Thus. uponmovement of the solenoid armature, that coil of the variometer connectedto the arm 17 will have its relative positioning with respect to theopposite coil varied, and in consequence, the total inductance of thegenerator circuit including variometer inductors 16, inductor 6' and theconductors 5, will be altered accordingly,

the generator circuit and the antenna system 8 for suificlentlyreducingcurrent in thempositioning of the solenoid arma-v that with thechange in the relative posi- 997i within the scope of anyfiilaimaficonsider whereby to destroy exact resonance between tenna circuit toproduce the desired signal, at the receiving station.

Instead of the arrangements shown in the preceding figures, it is to bealso understood that by placing the resonance destroying means in theso-called oscillatory circuit, the same may be as advantageouslyarrangpd in I the antenna circuit of the apparatus ass own in the Figure4. Herein t e oscillatory circuit is identified at ,5 and is coupled,inductively, at 6' to the antenna circuit 8' which latter circuit hasthe coils of a variometer 16' connectedin series therein as at 1.8; anarm 17 extends from one of said-coils and has the armature of a solenoid10 connected thereto, 'whereby with energization of the solenoid, the.arm 17' will be "caused to tic-T" cordin ly change the relativepositioning of the coi s of the variometer. An intelligence formingcircuit 12, oorres'pondi to thefir 35 cuits 12 and 12, is rovided t esolenoid 10, and obviously wiil afl'ord means for of} fecting theshifting of the arm 17'. 1

From the foregoing, it is to be understood tioning of the several coilsof the varioiheter, the capacitance of the antenna circuit will. bevaried, and by cons uence, resonance as between the same and t eoscillatory circuit will be destroyed Thus, the forming of intelligenceor signals. by thislintermittent destruction of resonance between theoscillatory and antenna circuits, is rendered possible. r

In the Figure 5, I have disclosed another, arrangement of means fordestroying resonance between the oscillatory and antenna circuits,wherein the antenna circuit 8 has a capacitance 19, arran ed in thesame, and] about which a second capacitance 9' is," shunted. To themovable element of the capacitance 9', the armature of the solenoid 10"is connected, being insulated therefrom as at 11". The terminals of thesolenoid 10 are connected to the opposite sides of an intelligenceforming circuit 12" corresponding to'the circuit 12 and therefore, withclosing of the key in said circuit, the solenoid 10" will be energized,thus varying the positioning of the movable element of the capacitance9' with relation to the fixed element thereof whereb to vary or changethe capacitance of t e' antenna circuit 8'; and conse uently destroyresonance, as between sai letory circuit in order-that theformi ofintelligence or signals may he practi lly' efi'ected. I o

Manifestly, the arrangements shown: throughout are capable or,considerah'l modification, and such lnodification as within the spiritof mgr-invention. \Iclaimr v y.

1, In radio transmitting apparatngbmii antenna circuit and theosci'l-R'J? women undam waves, a tuned oscillatory circuit shunts aboutthe generator of saidjtransmitting apparatus, an antenna circuit elec'trically connected to the tuned oscillatory circuit, said oscillatoryand antenna circuits being in exact resonance, a ca acitance shuntedabout the capacitance of t e tuned oscillatory circuit, and means forvaryin the relative positioning of the elements 0 said first capacitancewhereby to destroy resonance between the oscillatory and antennacircuits, at times, whereby the energy in said antenna circuit issubstantially interru ted.

2. 11 radio apparatus for transmitting undamped waves, a tunedoscillator circuit shunted about the generator oi said apparatus, anantenna circuit cou led to the tuned oscillatory circuit, sci

osci latory and antenna circuits be exact resonance, a capacitanceshunted a ut the capacitance of the tuned oscillate circuit havin one ofits elements move is, a solenoid, t e armature of said solenoid havmginsulated connection with said movable II element and the firstmentioned capacitance and an intelligence forming circult coupled tosaid solenoid for energizing the same whereby to val the relativepositioning of the elements 0 the first mentioned capaci- 30 tan'ce fordestroying the exact resonance between the oscillatory and antennacircuits, as and for the pur ose set forth.

. B. WOOLVERTON.

